Photoelectrochemical determination of cardiac troponin I based on rod-like g-C3N5@MnO2 heterostructure

Abstract

Rod-like graphite carbon nitride@MnO₂ (R-g-C₃N₅@MnO₂) heterostructure was prepared by in situ self-anchored growth of MnO₂ nanosheet on the surface of R-g-C₃N₅. The synthesized R-g-C₃N₅@MnO₂ heterostructure as photoactive material exhibited excellent photoelectrochemical (PEC) performance, and the prepared heterostructure-aptamer probe displayed sensitive PEC response to cTnI. Therefore, the PEC method was developed to detect cTnI based on the R-g-C₃N₅@MnO₂ heterostructure. It was found that the linear response to cTnI was in the range 0.001-30 ng/mL under optimized conditions, and the detection limit of the proposed sensor was 0.3 pg/mL. The PEC method displays stable photocurrent response up to 8 cycles and exhibited outstanding selectivity and sensitivity. The PEC method was successfully applied to detect cTnI in serum samples. The recoveries of cTnI detection in serums reach 95.5-104%, and the relative standard deviations range from 3.20 to 4.45%.

Keywords: Cardiac troponin I; MnO2 nanosheet; Photoelectrochemical method; Rod-like g-C3N5@MnO2 heterostructure.